Don't fail SCMName detection on non-IDN host names

Previously, when passing an URL with a host name that is not a valid IDN to SCMName::from, it failed with an IllegalArgumentException. This especially affects the case when the host name is an IP address. Make this method a bit more graceful by returning null instead.

Author: twz123

src/main/java/jenkins/scm/api/SCMName.java

@@ -105,15 +105,13 @@ private static String innerFromUrl(@NonNull String url, @CheckForNull List<Strin
         if (StringUtils.isBlank(hostName)) {
             return null;
         }
-        // let's see if we can make this more "friendly"
-        InternetDomainName host = InternetDomainName.from(IDN.toASCII(hostName));
-        if (host.hasPublicSuffix()) {
-            String publicName = host.publicSuffix().name();
-            hostName = StringUtils.removeEnd(StringUtils.removeEnd(host.name(), publicName), ".")
-                    .toLowerCase(Locale.ENGLISH);
-        } else {
-            hostName = StringUtils.removeEnd(host.name(), ".").toLowerCase(Locale.ENGLISH);
+
+        hostName = resolveInternetDomainName(hostName);
+        if (hostName == null) {
+            return null;
         }
+
+        // let's see if we can make this more "friendly"
         if (ignoredPrefixes != null) {
             for (String prefix : ignoredPrefixes) {
                 if (prefix.endsWith(".")) {
@@ -134,4 +132,20 @@ private static String innerFromUrl(@NonNull String url, @CheckForNull List<Strin
         }
         return hostName;
     }
+
+    private static String resolveInternetDomainName(String hostName) {
+        final InternetDomainName host;
+        try {
+            host = InternetDomainName.from(IDN.toASCII(hostName));
+        } catch (IllegalArgumentException notADomainName) {
+            return null;
+        }
+
+        if (host.hasPublicSuffix()) {
+            final String publicName = host.publicSuffix().name();
+            return StringUtils.removeEnd(StringUtils.removeEnd(host.name(), publicName), ".").toLowerCase(Locale.ENGLISH);
+        }
+
+        return StringUtils.removeEnd(host.name(), ".").toLowerCase(Locale.ENGLISH);
+    }
 }

src/test/java/jenkins/scm/api/SCMNameTest.java

@@ -68,4 +68,9 @@ public void given__url_with_idn__when__naming__then__punycode_is_roundtripped2()
         assertThat(SCMName.fromUrl("http://\u4F8B\u5B50.\u4E2D\u56FD/"), is("\u4F8B\u5B50"));
     }
 
+    @Test
+    public void given__url_with_ipv4address__when__naming__then__no_name_inferred() throws Exception {
+        assertThat(SCMName.fromUrl("http://127.0.0.1/scm"), is(nullValue()));
+    }
+
 }